Typographic mold



Patented June 19,1951

UNlTED STTES ATENT QFFICE TYPOGRAPHIC MOLD George H. Stryker,Philadelphia,

Pa., assignor to Lanston Monotype Machine Company, Philadelphia, Pa, acorporation of Virginia 2 Claims.

This invention relates to molds for casting elements of printing forms,such as printers types, and has for its principal object the productionof a mold provided with a vent or passage for the escape of air from themold cavity and entrancegate cavity, which vent is so located anddesigned as to result in the production of types of great solidity andstrength and having substantially perfect feet. This and other objectswill be more particularly described hereinafter in connection with thefollowing descriptionof the embodiment of the invention shown in theaccompanying drawings. Molds of this kind are adapted to be used with asuitable typographic casting machine, and the mold shown is for use inconnection with typecasting machines well known in the art as being theproduct of Lanston Monotype Machine Company. Such a machine is providedwith a pot for molten metal, a metal pump and nozzle and mechanismsconnected with the mold blade and with the cross block of the mold, aswell as being provided with other necessary mechanisms for the castingof type, all of these mechanisms operating in properly timed relation,as will readily be understood by those skilled in the art. A furtherdescription of this well-known typographic machine and its operation inassociation with the mold is deemed unnecessary.

An embodiment of the invention is shown in I the accompanying drawings,in which Fig. 1 is a plan view of the mold.

Fig. 2 is a cross section on substantially the line 2-2 of Fig. 1.

Fig. 3 is a cross section of the cross block on substantially the line33 of Fig. 2, with the adjoining water base and a type block shown indot and dash lines, and

Fig. 4 is a perspective View of the gate discharged from the mold andhaving the air vent fin attached to it.

The mold shown is generally of the construction shown in United StatesLetters Patent No. 2,029,529 issued in the name of M. C. Indahl andpatented Feb. 4, 1936. In both the patented mold and the mold shownherewith there are, for example, the base comprising the base plate 5and the Water base 2, also known as the squaring block, and the frontabutment 2a. Both molds include also the cross block 3 to operate atright angles to the mold blade 4, the end of which nearest the crossblock is slidable between adjacent ends of type blocks 5 and 6. The baseis also provided in molds of this kind with a conical nozzle opening 1,in which the pump nozzle seats and through which the molten metal isintroduced. The nozzle, as is well known, is lowered between castingsand rises to seat in the nozzle opening during the casting operation.The mold cavity or type cavity into which the metal is forced by thepump is formed as to its four sides by the type blocks, the mold bladeend and a face or wall of the cross block. It is understood, of course,that a matrix is ordinarily seated on top of these parts to form the topwall of the mold cavity.

These molds are also provided with a jet cavity or gate cavity below themold cavity, the side walls of said gate cavity being formed in thecross block, one end of the gate cavity being formed by the face of thewater base 2 against which the cross block slides and the other end ofsaid cavity being formed by the adjacent end wall of the gate pusher 8.The side walls 8a of the gate cavity slope upwardly to form aninverted-V cavity which the gate pusher fits and through which the metalfrom the nozzle is directed into the mold cavity. These side walls arethe adjacent walls of gate blocks 9 and H] which are beveled and locatedslightly apart and secured to the cross block top block 3a by screws, asis well known, these parts comprising the cross block proper. The gatepusher 8 is operative cross-wise of the cross block and is controlled'bythe usual cam H secured on the upper surface of the base I and effectiveto retract the pusher to provide the gate cavity at the time of castingand to move it toward the water base to eject the gate when the crossblock has been moved to gate ejecting position as shown in dotand-dashlines in Fig. 1. The ejected gate falls into the melting pot through theusual opening [2 shown dotted in Fig. 1. As usual, the cross block ismoved slightly in the opposite direction prior to moving to ejectingposition in order to sever the jet from the body of type cast into moldcavity.

In the usual construction of these molds the gate blocks 9 and l 0 arehighly finished near the gate cavity on the sides which slide upon thewater base, thus forming bearing pads 9 and I l:

but beyond these pads, in some constructions and as clearly shown inFig. 2, the faces of these sides are cut back slightly as indicated at9" and H)" as a clearance which in molds of generally used point sizesmay be about .00015 of an inch. The extremely narrow vertical slotbetween the gate block Ill and the water base thus formed by thisclearance space will be referred to hereinafter.

These molds or molds of the same general kind have been used for manyyears on the machines with which they are adapted to be used, but thetypes produced have at times been defective, particularly because of theundue amount of air entrapped in them. When a type was broken intopieces, this defect would appear as a relatively large bubble or asnumerous small cavities making the type weak so as not to stand up underprocesses which employ high pressures. The feet of such type may beill-formed and may have the condition known as bleeding feet. It ispossible to correct these defects in some cases by changing thetemperature of the molten metal, by altering the spring pressure exertedon the pump piston or the timing of pump and nozzle action or by otheradjustments of the casting machine. The present invention corrects thesedefects to a material extent and makes possible the production ofpractically perfect types without any of the .above mentionedmanipulations or adjustments being necessary. Nor are any suchadjustments necessary when molds of different point sizes aresubstituted one for the other, which was the practice formerly.

The bearing face or pad ID on the gate block I is provided, inaccordance with this invention, with a vent groove l3 shown extendingfrom the gate cavity to the end of the gate block so as to provide apassage from said cavity to the atmosphere at the time of casting. Thisgroove, in molds for the usual sizes of reading matter, is convenientlymade by a grinding wheel having a radius of about .0415 of an inch andis about .012 of an inch deep. Air which is driven from the moldcavities, through this groove traverses the groove to the end of theblock. The outer end of the groove l3 may be angled downwardly as at I4.Excess metal follows the air and to some extent travels with it, beingforced out of the end of the vent in a mist or dust. It is believed thatin molds provided with a clearance space H) between the water base andthe gate block ill, some air escapes into such clearance space, sincethe rod or fin 15' of metal which congeals in the vent after the ventstream has come to rest and which is attached to the gate [5 and isejected along with the gate, often has serrated or roughened edges, asshown at l5 in Fig. 4, indicating that air has escaped and in doing sohas produced these rough edges. It is evident however that the extremenarrowness of the clearance space is such that metal does notappreciably enter into it nor is it necessary in accordance with thespirit of this invention that a clearance space should be provided. Theportion M of the groove is preferably provided to direct air andspitting metal particles in a downward direction and toward the pot. Therod ejected with the gate 55, rarely extends as far as the slopingportion M of the vent groove but may do so in some cases, depending onconditions of the moment. The ejected gate and attached rod or fin fallsinto the pot through the usual opening [2 in the base. A shield or guardmay be suitably arranged, if desired, to catch and direct toward thepot, metal which may not have fallen directly into the pot.

It is to be understood that in molds and casting machines and especiallyin those which operate at a speed to produce 140 or more types perminute, there exists a pulsing of metal in the pump and nozzle so thatat each casting cycle when the nozzle is in removed position the metallevel therein may be at times low and at others relatively high; thusthe volume of air in the nozzle varies. At all times, when in thisremoved position, there is considerable air in the nozzle and when,later in the cycle of operation of the machine, the nozzle is raised toits position of being seated in the nozzle seat 1 and the pump pistonmoves in its operating stroke, such nozzle air, whatever its volume, isforced under pressure ahead of any metal into the gate and moldcavities. The nozzle air thus forced is released to the atmospherethrough the gate cavity and the vent passage l3, and when the metalfollows to stream into the mold cavity, air in such cavity is forcedbackwardly to escape, along with air in the gate cavity, through thesame vent. Excess metal,

" of course, finally iiows into the vent and it solidifies there as wellas in the gate cavity, after the pump ceases to force additional metalinto the cavities, being in the form of a fin or rod l5. This fin isdetached from the vent when the gate is ejected and both fin and gatefall into the pot as a single piece, as has been previously set forth.The result of the use of this construction is the production of typeshaving practically perfect lower ends, or feet, so that the types have afirm foundation on which to stand upright. This mold construction alsogives greater solidity to the types cast by it because of theircontaining a minimum amount of entrapped air, this extra degree ofsolidity being shown by the fact that types made by the vented molddescribed weigh materially more than when produced by molds ofconstructions known heretofore-even to the extent of 25% more.

I claim:

l. A typographic mold for producing single types, comprising a baseincluding a water-base, type blocks, a mold blade, a cross-block, saidblocks and blade forming a type cavity, one wall of the cross blockbeing slidable on the type blocks, said cross block including gateblocks forming an inverted V-gate cavity with a narrow slit connectionbetween the gate cavity and the type cavity, a wall of a gate blockbeing slidable on a wall of the water-base, a vent between said lastmentioned walls extending in the direction of movement of the slidablegate block and leading from the gate cavity to the atmosphere, wherebyduring the casting operation air and molten metal flow from said gatecavity through said vent and escape to the atmosphere before congealing,a gate pusher carried by the cross block and slidable in the gatecavity, and means carried by the base to move the pusher during theejection operation to eject the congealed gate and metal attached to itwhich has congealed in the vent.

2. A typographic mold for producing single types, comprising a baseincluding a water-base, type blocks, a mold blade, a cross block, saidblocks and blade forming a type cavity, one wall of the cross blockbeing slidable on the type blocks, said cross block including gateblocks forming an inverted V-gate cavity with a narrow slit connectionbetween the gate cavity and the type cavity, a wall of the gate blockbeing slidable on a wall of the water-base and having a highly finishedbearing pad in proximity to the gate cavity to fit against thewater-base wall on which it slides, but having a clearance space beyondthe pad to the end of the block, a vent in the form of a grooveextending across said pad and gate block from the gate cavity to the endof the block, and being deeper than said clearance space, whereby,during the casting operation air and molten metal flow through thegroove REFERENCES CITED The following references are of record in thefile of this patent:

UNITED STATES PATENTS Number Name Date 1,696,074 Barber Dec. 18, 19281,669,767 Lyons May 15, 1928 1,897,012 Severin Feb. 7, 1933 2,029,529Indahl Feb. 4, 1936 OTHER REFERENCES The Intertype; A Book ofInstruction for its 10 Operation and General Maintenance published bythe Intertype Corporation, 360 Furman St, Brooklyn 2, N. Y. Pages 82 and83, copyright 1943. (Copy in Division 17.)

